- Many plant species respond quickly to land management actions
- Serve as indicators of whether an area is moving in a more-or-less desirable direction
- Inform us whether a management action needs to be abandoned, increased, or maintained
- Serve as the main constituent of habitat quality
- Note we will not cover demography today.
June 5th 2024
Why do we monitor vegetation?
What variables are typically monitored?
- Absolute & Relative Cover How much of an area has vegetation? How is this cover composed by species and functional groups?
- preventing erosion, characterizing habitat.
- Abundance, Frequency, Density Are individual plants becoming patchier in areas? Is the population declining?
- Are actions too concentrated to microsites? Is a valuable resource declining?
- Are actions too concentrated to microsites? Is a valuable resource declining?
- Diversity How many species are there? How are their abundances distributed? Is an area down to only a few species?
- Overall ecosystem integrity, assessing conservation priorities.
How do we measure plant absolute cover?
Depends on vegetation type, and annual climatic variability
Forest
- Line Intercept
Grassland & Savannah
- Line Intercept (LI) & Line-Point Intercept (LPI)
- (Historic) Daubenmire
- Line Intercept (LI) & Line-Point Intercept (LPI)
Small plants!
- Grids with equal area cells
- most subjective of the methods
- complicated by time of sampling
- Grids with equal area cells
How do we measure plant abundance, frequency, and density?
- Belt Transects (abundance)
- plants are very sparse - pop. census size
- set up around LPI transects
- plants are very sparse - pop. census size
- Nested Quadrats (frequency)
- monitor multiple species simultaneously - spatial distribution / stability of populations
- Daubenmire frames also used
- monitor multiple species simultaneously - spatial distribution / stability of populations
- Quadrats (density)
- plants are moderately abundant - pop. census size, spatial distribution
- plants are moderately abundant - pop. census size, spatial distribution
How do we measure diversity?
- Can be done by wandering around areas…
- Quadrats
- Generally much larger than in other types of sampling
- Fewer replicates
- Generally much larger than in other types of sampling
- Need to be orientated to cross along environmental gradients
- The gold standard: Modified Whittaker
- MW has two less intensive follow-up variants, the ‘Intensive’ and ‘Extensive’
- I&E plots can characterize microhabitats (use determined via rarefaction)
- takes a long time…
What is Floristic Quality?
‘… tolerance of anthropogenic disturbance and exclusivity to remnant habitats are the only validated criteria for defining FQA.’
‘…FQA conveys two things about high conservative species: (1) All else being equal, they have greater conservation value, and (2) they reflect a site’s history of minimal disturbance and degradation.’
- Useful for identifying high-quality remnant habitat
- Essentially a format for prioritizing land management decisions, especially active management
- We know we cannot restore everywhere, preventing degradation is key, we can shift certain activities to areas of less conservation values
What do C-values mean?
- Vary by each administrative unit they are generated for
- Reflect the purpose of monitoring
’… the coefficient applied to each taxon represents a rank based on observed behavior and patterns of occurrence in Illinois plant communities and our confidence that a taxon is remnant (natural area) dependent.
Species given a C value of 0-1 are taxa adapted to severe disturbances, particularly anthropogenic disturbances…
Species with a C value of 2-3 are associated with somewhat more stable, though degraded, environments.
Species with coefficients 4-6 include many dominant or matrix species for several habitats; they have a high consistency of occurrence within given community types.
Species with C values 7-8 are taxa we associate mostly with natural areas, but that can be found persisting where the habitat has been degraded somewhat.
Species with coefficients 9-10 are considered to be restricted to high-quality natural areas.’
Calculations
- \(C_i\) in particular \(C\) is the Conservatism Value (C-Value), for each \(_i\) of the \(S\) at the site
- \(S\) is the number of species included in the calculation
- \(\overline{C}\) is the Mean Coefficient of Conservatism, or for short Mean C
- \(\sum{}\) is an operator, meaning that we will sum all C-Values, \(C\)
- \(S\) is the number of species included in the calculation
- \(\overline{C}\) is the Mean Coefficient of Conservatism, or for short Mean C
- \(\sqrt{S}\) is the square root of the number of species included in the calculation
- \(\sqrt{S}\) is the square root of the number of species included in the calculation
What do we mean by Species Richness?
- The number of plant taxa in an area; also referred to as \(\gamma-\text{diversity}\)
- Measuring it can be difficult (time intensive), as many plants are locally rare
- Progress towards characterizing it can be achieved via rarefaction
- \(\gamma-\text{diversity}\) , and it’s measurement, is influenced by two main traits
- the number of species per sub-habitats (\(\alpha-\text{diversity}\))
- the turnover in species between sub-habitats (\(\beta-\text{diversity}\))
- the number of species per sub-habitats (\(\alpha-\text{diversity}\))
Reading Plots
- Boundary Decisions
- Are plants rooted in the plot?
- Which side of the plots are plant rooted in?
- Order to reading?
- Nested quadrats go from smallest to largest plot
- Only record new species along the way
- If same species is present in ‘2’ as in ‘1’ do not record.
- Only record new species along the way
- Nested quadrats go from smallest to largest plot
- Avoiding double counting
- search methodically following a single direction
- Avoid trampling
- search methodically following a single direction
- Search in 1/2m wide swaths
Colored areas are “In” a plot.
Management Decisions - Species Cover
- Cover of species naturally ebb and flow
- Certain management actions can increase cover of some species, while vastly decreasing cover of others
- Many of the decreasing species may be important for wildlife, or ecosystem function (e.g. water retention, soil stability)
Rotating cattle near Wisdom MT. Agricultural Funders News
Management Decisions - Vegetation Similarity
- If we want to restore an area, what is our target?
- Example: We may want X% absolute cover of broad leaved shrubs w/ < X% relative cover of species Y
- But where do we get these standards from?
- Example: We may want X% absolute cover of broad leaved shrubs w/ < X% relative cover of species Y
- Reference site, an area with similar soils & climate to our site
- altered site should be able to produce a veg community similar to the reference
- altered site should be able to produce a veg community similar to the reference
- Can we expect areas with similar vegetation to respond similarly to management actions?
- e.g. fire, grazing cattle/sheep/goats, removal of invasives?
- e.g. fire, grazing cattle/sheep/goats, removal of invasives?
